Spectrophotometers having a monochromator to provide light of a known wavelength to the sample are usually precalibrated by mechanical adjustments made during manufacture. However, in precision analytical or research work it is desirable to be able to recheck and, if necessary, to readjust the wavelength scale to correct for mechanical or temperature induced changes. Where two monochromators are involved in a single instrument, such as in a fluorescence spectrophotometer for example, this could be a very time consuming adjustment requiring changes of the light source and the insertion of special samples, filters, etc. for transfer of light from the excitation monochromator to the emission monochromator.
It is an objective of the present invention to provide a build-in wavelength standard with means to couple it to the monochromator for calibration check.
It is a further objective to provide microprocessor controlled means for effecting said wavelength check.
It is a yet further objective to establish by software control an accurate readjustment or indexing of the wavelength.
It is an objective for a fluorescence spectrophotometer to follow up wavelength indexing on one monochromator with software executed indexing of the second monochromator.
It is an accompanying objective to obviate the necessity of operator attachment or removal of any part or appurtenance of the instrument during the recalibration process.
Yet a further objective is to extend said software controlled indexing of wavelength to other reference wavelengths and to double monochromators, where used.